1. DIMENSIONING REVIEW OR
YOU SHOULD HAVE LEARNED THIS STUFF IN Drafting 1
I KNOW, THAT WAS SOOOO LONG AGO

2. How to dimension round things
Arcs use radius
Radius symbol must precede measurement
HOLE DEPTH
THRU NEEDS NO NOTE
BLIND HOLE MUST HAVE DEPTH SPECIFIED
DEPTH SYMBOL MUST PRECEDE MEASUREMENT
Circles (holes and cylinders) use diameter
Diameter symbol must precede measurement
Holes in round view
Cylinders in rectangular view

3. Unidirectional vs aligned
Mechanical = unidirectional
Read everything from the bottom of the page!!
Architecture = aligned
Dimensions are parallel to the line they measure
We are not drawing houses!!
We do not use aligned dimensions!!!

4. Inches vs metric Inches Metric No leading zeros No inch marks
At least 2 places after decimal
Trailing zeros to fill two places or the required precision
Metric
Leading zero if less than 1
No mm required
No trailing zeros
MILLIMETERS UP TO THEN MEASURE WITH CENTIMETERS
INCHES METRIC

5. WHY DOES THIS OBJECT HAVE ONLY ONE VIEW?
ARE THESE THROUGH HOLES OR BLIND HOLES?
WHAT DOES THE 2 X MEAN?
WHERE SHOULD YOU GIVE MATERIAL THICKNESS?

6. WHAT DOES THIS SYMBOL MEAN?
WHAT INFORMATION IS NEEDED TO FULLY DESCRIBE A HOLE?
WHY ARE THERE MISSING DIMENSIONS? IS IT OK THESE DIMENSIONS ARE MISSING?

7. HOW CAN A HOLE AND THE CYLINDER IT IS IN BE THE SAME SIZE?
ALWAYS CHECK YOUR MATH!!
DO THE DIMENSIONS ADD UP?
WHAT TYPE OF SECTION IS THIS?

8. HOW CAN WE FIGURE THE DIAMETER OF THE CENTER LINE CIRCLE?
WHY ARE SOME ROUND OBJECTS DIMENSIONED IN THEIR ROUND VIEW AND SOME IN THEIR RECTANGULAR?
SHOULD THE DIMENSION BEHIND THE 2 X BE DIAMETER OR RADIUS?

9. MOVING FORWARD YOU NEED TO KNOW HOW TO DIMENSION
FIRST GO BACK AND ADD DIMENSIONS TO YOUR EXTRUDES, PRINT THEM AND TURN THEM IN
YOU WILL BE ADDING DIMENSIONS TO ALL YOUR DRAWINGS
WHEN COMPLETING DRAWINGS OUT OF THE TEXTBOOK MAKE SURE YOU USE ALL THE DIMENSIONS IN THE TEXTBOOK. NO MORE, NO LESS!!
WHEN DRAWING A PART YOU MEASURED, THINK!!! WHAT DIMENSIONS ARE NEEDED TO FULLY DESCRIBE THE OBJECT. TOO MANY DIMENSIONS ARE ALMOST AS BAD AS NOT ENOUGH.